酶解和碱处理对半乳糖醛酸-木素脱氢聚合物复合体结构的影响

Effect of Enzymatic and Alkaline Treatment on the Structures of the Galacturonic acid-DHP Complex

中文关键词:  半乳糖醛酸-木素脱氢聚合物复合体  果胶酶  漆酶  13C-NMR

Key Words:galacturonic acid-DHP complex  pectinase  laccase  13C-NMR

中文摘要:

      以果胶结构单元D-半乳糖醛酸和木素前驱物松柏醇-β-D-葡萄糖苷为原料，在多种生物酶的协同作用下合成了半乳糖醛酸-木素脱氢聚合物复合体（GDHPC），并分别用酶解（果胶酶）和碱法（1 mol/L的NaOH）对GDHPC进行处理。FT-IR和13C-NMR分析表明，D-半乳糖醛酸和木素脱氢聚合物之间形成了以苯甲醚键和酯键2种形式连接的木素-碳水化合物连接键；酶解和碱法处理都能在一定程度上削弱D-半乳糖醛酸的特征峰；碱法处理能降解酯键，但对苯甲醚键的降解作用并不明显；酶解对酯键和苯甲醚键的降解效果均较差。

Abstract:

      In order to illustrate the chemical bonds between galacturonic acid and lignin dehydrogenation polymer (DHP), galacturonic acid-DHP complexes (GDHPC) were prepared from galacturonic acid and coniferin in the presence of enzymes and with various enzymes synergetic action. The FT-IR and 13C-NMR spectra indicated that DHP and galacturonic acid were connected by two kinds of lignin-carbohydrate linkage (LC bond), i.e. ester bond and benzyl ether bond. The changes of LC bonds after treating the GDHPC with pectinase and 1 mol/L sodium hydroxide solution were also investigated respectively. The FT-IR and 13C-NMR spectra showed that the content of D-galacturonic acid decreased after the two kinds of treatments. It was found that the benzyl ether bond could not be degraded, however, the ester bonds was degraded completely by sodium hydroxide solution treatment. None of the two kinds of LC bonds was degraded after pectinase treatment. The cleavage mechanism of LC bonds in soda pulping process and low efficiency with pectinase treatment was discussed theoretically.